
(define (+ a b)
    (if (= a 0)
        b
        (inc (+ (dec a) b))))

;(+ 4 5)
;(inc (+ (dec 4) 5))
;(inc (+ 3 5))
;(inc (inc (+ 2 5)))
;(inc (inc (inc (+ 1 5))))
;(inc (inc (inc (inc (+ 0 5)))))
;(inc (inc (inc (inc 5))))
;(inc (inc (inc 6)))
;(inc (inc 7))
;(inc 8)
;9
; processo recursivo

(define (+ a b)
    (if (= a 0)
        b
        (+ (dec a) (inc b))))

;(+ 4 5)
;(+ (dec 4) (inc 5))
;(+ 3 6)
;(+ (dec 3) (inc 6))
;(+ 2 7)
;(+ (dec 2) (inc 7))
;;(+ 1 8)
;(+ (dec 1) (inc 8))
;(+ 0 9)
;9
; processo iterativo
